This invention relates to a method of forming an oxide film on a metallic member for a dental treatment and, in particular, to a method of forming an oxide film to adhere a metallic member to an object by the use of an adhesive.
Traditionally, a metallic member is often fixed on a dental treatment through an adhesive to a fixing site, such as an affected part of a patient""s tooth. As a metallic material in a dental field, known is an orthodontic bracket, a crown or a bridge as a prosthetic material, or an inlay for conservative restoration.
As the adhesive used in dental treatment, a dental cement is known. As an existing adhering technique, the following methods are adopted in order to improve the adhesive strength between the metallic member and the dental cement.
As a first adhering method, the surface of the metallic member is sandblasted. In this state, the metallic member is placed on the affected part of the patient as the fixing site through the dental cement and fixed by the dental cement.
As a second adhering method, the metallic member to be adhered is heated in an electric furnace to be oxidized. Thereafter, the metallic member is adhered to the fixing site. When the metallic member is oxidized and is adhered to the fixing site through the dental cement, an oxide film is helpful to firmly secure the metallic member to the fixing site. This is because the adhesive such as the dental cement has an improved wettability due to the presence of the oxide film.
Taking the above into consideration, an oxide film has been usually formed on a whole surface of the metallic member. Thus, the metallic member with the oxide film is placed onto the affected part of the patient. In this event, the oxide film should be partially removed or polished from the metallic member to obtain a mirror-finished surface before the metallic member is placed onto the affected part of the patient, on account of the fact that the dental cement as the adhesive is partially coated on the metallic member.
On the other hand, an implant used in the dental field may be directly implanted in the affected part of the patient to be bonded to a living bone after the implant is heated and oxidized in the electric furnace. In this case, the implant acts as the metallic member while the living bone, the fixing site.
At any rate, a very long time is required to polish the oxide film on the metallic member before placement of the metallic member onto the fixing site. In addition, the metallic member may be deteriorated in quality because it is heated in the electric furnace in order to oxidize the surface.
It is an object of this invention to provide a method of forming an oxide film on a metallic member, which is capable of avoiding deterioration of the metallic member that might occur on forming the oxide film at high temperature.
It is another object of this invention to provide a method of the type described, which dispenses with long time polishing before placement of the metallic member onto the fixing site.
It is still another object of this invention to provide a method of the type described, which is capable of improving reliability and strength in adhesion.
According to this invention, there is provided a method of forming an oxide film a metallic member, the method comprising the steps of (1) selectively applying a hydrogen peroxide solution onto a partial surface of the metallic member and (2) irradiating a light beam onto the partial surface through the hydrogen peroxide solution to selectively and locally form the oxide film onto the metallic member. The light beam is selected from a group consisting of a visible ray, a laser beam, and an ultraviolet ray.
The metallic member may be made of a material selected from a group comprising a cobalt-chromium alloy, a nickel-chromium alloy, a stainless steel, pure titanium, a titanium alloy, a platinum gold alloy, a gold-silver-palladium alloy, a silver alloy, and a gold alloy.
The metallic member may be an implant to be implanted in a living bone.